Focusing Actuator for Magneto-optical Disk Drives

Magneto-optical disk drives have some disadvantages compared with hard disk drives such as low access speed and low data rate. A small light optical head and high speed rotation of the disk would improve the performance, as well as achieving over write. This paper details the development of small-light focusing actuator, which can be used in high speed rotation of disk and make optical head small and thin. The actuator suspension, which raises the frequencies of higher order mechanical resonance, is discussed. And a parallel leaf spring suspension with visco-elastic damping layer is adopted. The vibration characteristics were experimentally evaluated. Results show that the frequencies of higher order mechanical resonance are above 50 kHz. The actuator is driven by a novel moving coil motor which makes the moving part thin and stiff. The design and performance of the motor are clarified.